PETERBILT HAT EMBROIDERED FLEXFIT CURVED BILL HAT SIZESS/M (6 3/4" - 7 1/4")L/XL (7 1/8" - 7 5/8")XL/XXL (7 3/8" - 8") Additional Features: Athletic shape. Hard buckram. 8 rows of stitching on visor. Silver undervisor. HOW TO MEASURE Measure the circumference around the head,above the eyebrow and at the widest part of the head.Divide number by 3.14 for hat size